1. Field of the Invention
The present invention relates to a cylinder assembly comprising a large number of hydraulic cylinders.
2. Explanation of Related Art
Japanese Patent Public Disclosure No. 6-190464 recited a conventional example of the cylinder assembly of this type. The conventional cylinder assembly comprises a large number of hydraulic cylinders arranged in a horizontal direction. A housing of every hydraulic cylinder has a lower end wall fixed to a support pedestal. A hydraulic chamber is formed between a piston inserted into the housing and the lower end wall. The respective hydraulic chambers are connected to a hydraulic source via hydraulic pipes.
There has been a desire for improving the conventional technique on the following points.
Hydraulic pipes must be connected to each of the large number of hydraulic cylinders in a narrow and limited piping space, which entails a problem of troublesome piping work. Further, the hydraulic pipes require a huge quantity of joints, which invites an easy leakage of pressurized oil.
The present invention has an object to provide a cylinder assembly which facilitates the piping work and can prevent the leakage of the pressurized oil.
In order to accomplish the above-mentioned object, the present invention has constructed the cylinder assembly in the following manner, for example, as shown in FIG. 1.
There is provided a manifold 2 having a passage 4 to which pressurized oil is supplied. A plurality of hydraulic cylinders 7 are detachably attached to the manifold 2. Each of the hydraulic cylinders 7 comprises a housing 12 hermetically fixed to a support surface 9 of the manifold 2, a piston 14 hermetically inserted into the housing 12 and a hydraulic chamber 15 which is formed between the piston 14 and the support surface 9, and directly opposes to the support surface 9. The manifold 2 has an interior area provided with branched passages 17. Every branched passage 17 has one end communicated with the passage 4 and has the other end communicated with the hydraulic chamber 15.
The present invention offers the following function and effect.
When supplying pressurized oil to the plurality of hydraulic cylinders, the pressurized oil is supplied to the passage of the manifold. Then the pressurized oil is supplied to every hydraulic chamber of every hydraulic cylinder through the passage and each of the branched passages.
As such, the pressurized oil can be supplied to the hydraulic chambers through the passage and the branched passages formed within the manifold. There is no need of connecting hydraulic pipes to each of the hydraulic cylinders. This facilitates the piping work for the cylinder assembly. Further, the number of joints is decreased by an amount corresponding to the omission of the hydraulic pipes to result in the possibility of preventing the pressurized oil from leaking out of the cylinder assembly.
Additionally, the manifold has its support surface directly opposed by the hydraulic chamber within the housing. Therefore, a front wall portion of the support surface can serve as an end wall of the hydraulic chamber. This has made it possible to remove the end wall for the hydraulic chamber from the housing. As a result, the cylinder assembly can be manufactured with a simple structure at a low cost and besides facilitates the maintenance. Besides, the removal of the end wall decreases the height of the housing to result in the possibility of making the cylinder assembly compact.
The present invention includes the following cylinder assembly.
For instance, as shown in FIG. 1, the manifold 2 is provided with another passage 5 and the housing 12 has its interior area formed with an air vent passage 18. The air vent passage 18 has one end communicated with the another passage 5 and has the other end communicated with an upper portion of the hydraulic chamber 15. The invention can expel air within the hydraulic chamber to an exterior area through the air vent passage and the another passage when the pressurized oil has been supplied to the hydraulic chamber. Accordingly, it can effect air venting for every hydraulic cylinder substantially completely. This assures a reliable and smooth operation of the cylinder assembly.
The present invention further includes the following cylinder assembly.
For example, as shown in FIG. 4, the housing 12 has a cylinder bore 13 in which an annular attaching groove 46 is formed. A sealing member 45 attached to the attaching groove 46 seals the piston 14. The sealing member 45 has a lower side provided with a cavity 53, with which the air vent passage 18 communicates.
The present invention still more includes the following cylinder assembly.
For example, as shown in FIG. 4, at least one of the upper portion of the hydraulic chamber 15 and the air vent passage 18 is provided with a flow resistance applying means.